41 resultados para Retaining wall. Instrumentation. Anchors

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo (BDPI/USP)


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Root canal treatment is a frequently performed dental procedure and is carried out on teeth in which irreversible pulpitis has led to necrosis of the dental pulp. Removal of the necrotic tissue remnants and cleaning and shaping of the root canal are important phases of root canal treatment. Treatment options include the use of hand and rotary instruments and methods using ultrasonic or sonic equipment. OBJECTIVES: The objectives of this systematic review of randomized controlled trials were to determine the relative clinical effectiveness of hand instrumentation versus ultrasonic instrumentation alone or in conjunction with hand instrumentation for orthograde root canal treatment of permanent teeth. MATERIAL AND METHODS: The search strategy retrieved 226 references from the Cochrane Oral Health Group Trials Register (7), the Cochrane Central Register of Controlled Trials (CENTRAL) (12), MEDLINE (192), EMBASE (8) and LILACS (7). No language restriction was applied. The last electronic search was conducted on December 13th, 2007. Screening of eligible studies was conducted in duplicate and independently. RESULTS: Results were to be expressed as fixed-effect or random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confdence intervals. Heterogeneity was to be investigated including both clinical and methodological factors. No eligible randomized controlled trials were identifed. CONCLUSIONS: This review illustrates the current lack of published or ongoing randomized controlled trials and the unavailability of high-level evidence based on clinically relevant outcomes referring to the effectiveness of ultrasonic instrumentation used alone or as an adjunct to hand instrumentation for orthograde root canal treatment. In the absence of reliable research-based evidence, clinicians should base their decisions on clinical experience, individual circumstances and in conjunction with patients' preferences where appropriate. Future randomized controlled trials might focus more closely on evaluating the effectiveness of combinations of these interventions with an emphasis on not only clinically relevant, but also patient-centered outcomes.

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Several studies have reported the benefits of sonic and/or ultrasonic instrumentation for root debridement, with most of them focusing on changes in periodontal clinical parameters. The present study investigated possible alterations in the tensile bond strength of crowns cemented with zinc phosphate cement to natural teeth after ultrasonic instrumentation. Forty recently extracted intact human third molars were selected, cleaned and stored in physiologic serum at 4°C. They received standard preparations, at a 16º convergence angle, and AgPd alloy crowns. The crowns were cemented with zinc phosphate cement and then divided into four groups of 10 teeth each. Each group was then subdivided into two subgroups, with one of the subgroups being submitted to 5,000 thermal cycles ranging from 55 ± 2 to 5 ± 2°C, while the other was not. Each group was submitted to ultrasonic instrumentation for different periods of time: group 1 - 0 min (control), group 2 - 5 min, group 3 - 10 min, and group 4 - 15 min. Tensile bond strength tests were performed with an Instron testing machine (model 4310). Statistical analysis was performed using ANOVA and Tukey's test at the 5% level of significance. A significant reduction in the tensile bond strength of crowns cemented with zinc phosphate and submitted to thermal cycles was observed at 15 min (196.75 N versus 0 min = 452.01 N, 5 min = 444.23 N and 10 min = 470.85 N). Thermal cycling and ultrasonic instrumentation for 15 min caused a significant reduction in tensile bond strength (p < .05).

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PURPOSE: To evaluate an experimental animal model to study the abdominal tissue activity considering its interaction with a polypropylene mesh, through the use of one of the optical phenomena of light Laser, the biospeckle. METHODS: Fifty Wistar male rats were divided into four groups: Group 1: ten animals not submitted to surgery; Group 2: ten animals submitted to surgery without polypropylene mesh; Group 3: 20 animals submitted to surgery followed by the mesh placement; Group 4: (sham) with ten animals. None of the animals presented post surgical complications being submitted to the optical tests at the 20th postoperative day. RESULTS: The analysis from the biospeckle tests, comparing the medians and standard deviations with T Student test, indicated that no significative difference was observed on the abdominal wall tissue activity in the four groups considered, with and without polypropylene mesh prosthesis implantation. CONCLUSION: The animal model is viable and the biospeckle open ways for a great number of experiments to be developed in evaluating tissue activity.

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In this work it is presented the development of a simple, portable and inexpensive instrumentation for amperometric and coulometric detection in different analytical instrumentation systems utilizing ultramicroelectrodes. The software, developed in LabVIEW 7.1TM, is capable to carry out three main detection techniques (amperometric, pulsed amperometric and coulometric detection) and a voltammetric technique (cyclic voltammetry). The instrumentation was successfully evaluated using the following systems: cyclic voltammograms of metallic electrodes in alkaline solutions, flow electrochemical detection of glucose and glycine and direct determination of herbicide glyphosate (electrochemical detection coupled to HPLC).

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This research work focuses on the analysis of hydraulic transients in polyvinyl chloride (PVC) pipes, which are characterized by a viscoelastic rheological behavior. Transient pressure data were collected in a pipe rig consisting of a set of PVC pipes. The creep function of the PVC pipes was determined by using an inverse transient model based on collected transient pressure data and compared with that obtained by carrying out mechanical tensile tests of PVC pipe specimens. The numerical results obtained from the transient solver have shown that the attenuation, dispersion, and shape of transient pressures were well described. The incorporation of the viscoelastic mechanical behavior in the hydraulic transient model has provided an excellent fitting between numerical results and observed data. Calibrated creep function based on inverse analysis fit the one determined by mechanical tests well, which emphasized the importance of pipe-wall viscoelasticity in hydraulic transients in PVC pipes.

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The magnetic Barkhausen noise (MBN) is a phenomenon sensitive to several kinds of magnetic material microstructure changes, as well as to variations in material plastic deformation and stress. This fact stimulates the development of MBN-based non-destructive testing (NDT) techniques for analyzing magnetic materials, being the proposition of such a method, the main objective of the present study. The behavior of the MBN signal envelope, under simultaneous variations of carbon content and plastic deformation, is explained by the domain wall dynamics. Additionally, a non-destructive parameter for the characterization of each of these factors is proposed and validated through the experimental results. (C) 2010 Elsevier B.V. All rights reserved.

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Intravascular ultrasound (IVUS) image segmentation can provide more detailed vessel and plaque information, resulting in better diagnostics, evaluation and therapy planning. A novel automatic segmentation proposal is described herein; the method relies on a binary morphological object reconstruction to segment the coronary wall in IVUS images. First, a preprocessing followed by a feature extraction block are performed, allowing for the desired information to be extracted. Afterward, binary versions of the desired objects are reconstructed, and their contours are extracted to segment the image. The effectiveness is demonstrated by segmenting 1300 images, in which the outcomes had a strong correlation to their corresponding gold standard. Moreover, the results were also corroborated statistically by having as high as 92.72% and 91.9% of true positive area fraction for the lumen and media adventitia border, respectively. In addition, this approach can be adapted easily and applied to other related modalities, such as intravascular optical coherence tomography and intravascular magnetic resonance imaging. (E-mail: matheuscardosomg@hotmail.com) (C) 2011 World Federation for Ultrasound in Medicine & Biology.

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Few molecular studies have been devoted to the finger drop process that occurs during banana fruit ripening. Recent studies revealed the involvement of changes in the properties of cell wall polysaccharides in the pedicel rupture area. In this study, the expression of cell-wall modifying genes was monitored in peel tissue during post-harvest ripening of Cavendish banana fruit, at median area (control zone) and compared with that in the pedicel rupture area (drop zone). To this end, three pectin methylesterase (PME) and seven xyloglucan endotransglycosylase/hydrolase (XTH) genes were isolated. The accumulation of their mRNAs and those of polygalaturonase, expansin, and pectate lyase genes already isolated from banana were examined. During post-harvest ripening, transcripts of all genes were detected in both zones, but accumulated differentially. MaPME1, MaPG1, and MaXTH4 mRNA levels did not change in either zone. Levels of MaPME3 and MaPG3 mRNAs increased greatly only in the control zone and at the late ripening stages. For other genes, the main molecular changes occurred 1-4 d after ripening induction. MaPME2, MaPEL1, MaPEL2, MaPG4, MaXTH6, MaXTH8, MaXTH9, MaEXP1, MaEXP4, and MaEXP5 accumulated highly in the drop zone, contrary to MaXTH3 and MaXTH5, and MaEXP2 throughout ripening. For MaPG2, MaXET1, and MaXET2 genes, high accumulation in the drop zone was transient. The transcriptional data obtained from all genes examined suggested that finger drop and peel softening involved similar mechanisms. These findings also led to the proposal of a sequence of molecular events leading to finger drop and to suggest some candidates.

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Background: Surgical resection in locally advanced breast cancer produces large defects that may not be suitable for primary closure. Immediate reconstruction is controversial and presents a complicated scenario for breast surgeons and plastic surgeons. Methods: In this study, a different design was planned for the latissimus dorsi musculocutaneous flap with primary closure in V-Y for the correction of major lesions in the anterior chest wall. Twenty-five patients underwent immediate locally advanced breast cancer reconstruction with a V-Y latissimus dorsi musculocutaneous flap. This flap was raised from adjacent tissue located on the lateral and posterior thoracic region and presented a triangular shape whose base was the lateral aspect of the mastectomy wound. The technique was indicated in patients with large thoracic wounds. Results: Mean follow-up time was 16 months. Closure was obtained in the donor and recipient sites without the use of skin grafts or other more major procedures. Complications occurred in nine patients (36 percent), including dorsal wound dehiscence in five patients and seroma in three. All cases except one were treated by a conservative approach with a good result. No total flap loss was reported. All patients achieved a satisfactory thoracic reconstruction and adequate wound care. Conclusions: The V-Y latissimus dorsi musculocutaneous flap is a reliable technique for immediate locally advanced breast cancer reconstruction. The technique is advantageous because the V-Y design allows primary closure of the chest wound and donor defect. Success depends on patient selection, coordinated planning with the breast cancer surgeon, and careful intraoperative management. (Plast. Reconstr. Surg. 127: 2186, 2011.)

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A study was carried out to evaluate the feasibility of autologous adipose derived stem cells (ADSC) transplantation into female rabbits` urethra walls as an alternative to intrinsic urethral regeneration. Inguinal fat pad of 12 New Zealand adult female rabbits were harvested and processed to obtain stromal vascular fraction (SVF). The SVF were platted to isolate ADSC. Before urethral injection, cells were labeled with DiI marker. The urethra wall was injected with 1 x 10(7) autologous cells or saline (sham). The urethra was harvested at 2, 4, and 8 weeks to identify DiI-labeled cells. At 2 and 4 weeks, the ADSCs create a nodule localized in the urethral sub-mucosa. At 8 weeks, the ADSCs spread and integrated with the urethra wall from the initial injection site. This is the first study to demonstrate a successful autologous ADSCs transplantation. It confirms that ADSCs can survive and integrate within the urethral wall.

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Becker LE, Koleganova N, Piecha G, Noronha IL, Zeier M, Geldyyev A, Kokeny G, Ritz E, Gross ML. Effect of paricalcitol and calcitriol on aortic wall remodeling in uninephrectomized ApoE knockout mice. Am J Physiol Renal Physiol 300: F772-F782, 2011. First published December 15, 2010; doi:10.1152/ajprenal.00042.2010.-Despitean only minor reduction in the glomerular filtration rate, uninephrectomy (UNX) markedly accelerates the rate of growth of atherosclerotic plaques in ApoE-/- mice. It has been suggested that vitamin D receptor (VDR) activation exerts an antiproliferative effect on vascular smooth muscle cells, but the side effects may limit its use. To assess a potentially different spectrum of actions, we compared the effects of paricalcitol and calcitriol on remodeling and calcification of the aortic wall in sham-operated and UNX ApoE-/- mice on a diet with normal cholesterol content. Sham-operated and UNX mice were randomly allotted to treatment with solvent, calcitriol (0.03 mu g/kg) or paricalcitol (0.1 mu g/kg) 5 times/wk intraperitoneally for 10 wk. Semithin (0.6 mu m) sections of the aorta were analyzed by 1) morphometry, 2) immunohistochemistry, and 3) Western blotting of key proteins involved in vascular calcification and growth. Compared with sham-operated animals (5.6 +/- 0.24), the wall-to-lumen ratio (x100) of the aorta was significantly higher in solvent-and calcitriol-treated UNX animals (6.64 +/- 0.27 and 7.17 +/- 0.81, respectively, P < 0.05), but not in paricalcitol-treated UNX (6.1 5 +/- 0.32). Similar differences were seen with respect to maximal plaque height. Expression of transforming growth factor (TGF)-beta 1 in aortic intima/plaque was also significantly higher in UNX solvent and UNX calcitriol compared with sham-operated and UNX paricalcitol animals. Treatment with both paricalcitol and calcitriol caused significant elevation of VDR expression in the aorta. While at the dose employed paricalcitol significantly reduced TGF-beta expression in plaques, calcitriol in contrast caused significant vascular calcification and elevated expression of related proteins (BMP2, RANKL, and Runx2).

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Background and Aim: Although prophylaxis with beta-blockers has been shown to decrease variceal pressure and wall tension in cirrhotic patients, this has not been demonstrated in non-cirrhotic portal hypertension caused by Schistosoma mansoni infection. Methods: Thirteen patients without history of previous gastrointestinal bleeding were included. All of them had high-risk esophageal varices at endoscopy. An endoscopic gauge and a high-frequency endoscopic ultrasonography miniprobe were used to assess transmural variceal pressure and wall tension before and after achieving beta-blockade with propranolol. Results: Baseline variceal pressure decreased from 13.3 +/- 3.5 to 8.2 +/- 2.0 mmHg (P < 0.0001) and wall tension from 500.2 +/- 279.8 to 274.0 +/- 108.3 mg.mm-1. The overall effect of propranolol on decreasing variceal pressure and wall tension expressed in percentage change in relation to baseline values was 35.7 +/- 18.4% and 35.9 +/- 26.7%, respectively (P = 0.9993). Conclusion: Propranolol significantly reduced variceal pressure and wall tension in schistosomiasis.

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Objective: To assess the association between the depth of trophoblastic penetration into the tubal wall with serum concentrations of vascular endothelial growth factor (VEGF) and beta-hCG and to assess its predictive value. Design: Prospective study. Setting: Tertiary care university hospital. Patient(s): Thirty patients with ampullary pregnancy undergoing salpingectomy were analyzed. Intervention(s): Trophoblastic invasion was histologically classified as stage I when limited to the tubal mucosa, stage II when extending to the muscle layer, and stage III in the case of complete tubal wall infiltration. Main Outcome Measure(s): The relation between depth of trophoblastic infiltration into the tubal wall with VEGF and beta-hCG serum concentrations on the day of surgery. Result(s): An association between the depth of trophoblastic invasion and maternal serum concentrations of VEGF and beta-hCG was observed. VEGF levels of 297.2 pg/mL showed 100.0% sensitivity and 90.0% specificity for stage I, and levels of 440.1 pg/mL showed 81.8% sensitivity and 88.8% specificity for stage III. Beta-hCG levels of 2590.0 mIU/mL showed 88.9% sensitivity and 80.0% specificity for stage I, and levels of 10,827.0 mUI/mL showed 72.7% sensitivity and 88.9% specificity for stage III. Conclusion(s): Maternal serum VEGF and beta-hCG concentrations are associated with depth of trophoblastic penetration into the tubal wall. (Fertil Steril (R) 2010;94:1595-600. (C) 2010 by American Society for Reproductive Medicine.)

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Background: Structural and inflammatory changes in asthma involve both the large and small airways, with involvement of the distal lung being related to disease severity. We have previously shown that changes in the extracellular matrix (ECM) composition of the distal lung are associated with loss of alveolar attachments in patients with fatal asthma. However, major ECM elements, such as collagen I and fibronectin and their regulators, have not been addressed at the distal level. Objective: We sought to evaluate ECM remodeling in the distal lungs of asthmatic patients. Methods: Using immunohistochemistry and image analysis, we determined the content of collagen I and III, fibronectin, and matrix metalloproteinases; (MMPs) 1, 2, and 9 and tissue inhibitors of metalloproteinase (MMPs) 1 and 2 in the large and small airways and lung parenchyma of 24 patients with fatal asthma and compared the results with those of 11 nonasthmatic control subjects. Protein content was defined as the area of positive staining divided by basement membrane or septum length. Results: We observed increased collagen I and decreased collagen III content in the small airways of asthmatic patients compared with that seen in control subjects. Greater fibronectin and MMP-1, MMP-2, and MMP-9 content was observed at the outer area of the small airways in asthmatic patients. NIMP content was also increased in the peribronchiolar parenchyma in asthmatic patients. In contrast, TIMP expression was only increased in the large airways of asthmatic patients compared with that seen in control subjects. Conclusions: The outer area of the small airways is a major site of ECM remodeling in fatal asthma, potentially contributing to functional changes and the loss of airway-parenchyma interdependence observed in patients with fatal asthma. (J Allergy Clin Immunol 2009;123:1090-7.)